Want colder A/C? Try power washing your AC condenser at the car wash. - Page 2 - PeachParts Mercedes-Benz Forum

Jarod · #16 07-09-2021, 01:23 PM

Quote:

Originally Posted by 123boy

I "stumbled" upon this guy a couple weeks ago. Maybe he's already well known (or, infamous lol) in "these parts"? Some "purists" will say he's a little unorthodox and heavy handed, maybe? Dunno. He seems to get good results and his vids are done pretty well. Give him a look. He has a bunch of W123 related common problem solvers. Seems like a nice enough dude.....not at all pretentious or on a high horse. I like how he just "goes after it".....lol
His "aux cooling fan rebuild" is really good. Check out his "channel".
https://www.youtube.com/watch?v=-ydCsCSxiiA&t=454s

Oh Hi! Thats me!
I'm certainly no purist, but I do like my cars to be relatively close to original aside from some "improvements", at first I was a bit taken aback by unorthodox and heavy handed but then I thought well... yeah he kinda has a point lol!

Be warned, the "aux fan mod" with the relays and such you linked was intended as a proof of concept, leaving the wires just shoved into the OEM relay connections was never intended to be a permanent solution.

I would LOVE to figure out what kind of pins/connectors are used for the various electronics, I'd 3d print some adapters that could just get plugged in.
If anyone knows what size/style pins/sockets could be used, I'd love to get a pile of them for some projects!

With the adjustments and "improvements" I've made to my blue cars AC, my wife was so impressed she said it feels like a new car, it gets too cold to keep on full blast, so the temperature wheel gets set around the 70F range and we let it do its magic!

If that isn't the seal of approval, I'm not sure what is

123boy · #17 07-09-2021, 06:51 PM

hahahaha....small world, that's for sure! Didn't mean any offense. I like your videos. Good information. I think it's great the way you just tear into a project on these cars. Honest presentations and you don't "beat around the bush", so to speak. Very refreshing, imho. I don't know how many other members, on here, also post vids. But, I know that videos are difficult and time consuming to produce and the "end result" isn't always the greatest. Yours seem to turn out very well and the info is clear and concise. Also "props" for the links you add to find parts, etc. used in the vid.
Maybe the "Pelican moderator" could start a link/list of members' YT presentations? Possibly already has as I'm not "up to the minute" on any of this stuff.....
Keep up the good work!
Cheers!

ykobayashi · #18 07-22-2021, 10:43 PM

Hey! I just watched that video and did two of your mods. The 100% recirc mod and the relay mod for the aux fan.

I need just a little more cooling. Mine is okay for the socal coast but I need a few more degrees drop. We are having some CA “humidity” right now (58%

) and my R134a + parallel flow combo is just keeping up at 90 deg F.

I used to hardwire my aux fan on at the Temp switch but it was on all the time and it was annoying. It’s really hard to get down there on a 85 300D CA emissions model. It did help. But last winter it got disconnected and I misplaced the jumper.

I decided I wanted to try the relay trick. First I thought why a relay? I figured I’d just energize the coil on the ice cube relay with a wire from the AC clutch relay. Doh! The 300d needs the coil on the aux fan relay to be pulled to ground to turn on. Then I realized an 85 only has one ice cube relay for the fan and the clutch is handled by the Klima. So instead of jumping the relay like in the video I just used Klima pin 7 to activate the extra automotive relay.

Haven’t figured out a nice way to piggy back the connections yet. For the time being I jammed he wires in the holes like in your video.

Thanks Jarod. I love free (had a T and relay in the junk box) fixes. I’m going to drive out now and see how it works.

I guess if I need more cooling there’s the double condenser trick and isobutane refrigerants. Hopefully this will get me another few degrees.

Jarod · #19 07-26-2021, 10:43 AM

Quote:

Originally Posted by ykobayashi

Hey! I just watched that video and did two of your mods. The 100% recirc mod and the relay mod for the aux fan.

I need just a little more cooling. Mine is okay for the socal coast but I need a few more degrees drop. We are having some CA “humidity” right now (58%

) and my R134a + parallel flow combo is just keeping up at 90 deg F.

I used to hardwire my aux fan on at the Temp switch but it was on all the time and it was annoying. It’s really hard to get down there on a 85 300D CA emissions model. It did help. But last winter it got disconnected and I misplaced the jumper.

I decided I wanted to try the relay trick. First I thought why a relay? I figured I’d just energize the coil on the ice cube relay with a wire from the AC clutch relay. Doh! The 300d needs the coil on the aux fan relay to be pulled to ground to turn on. Then I realized an 85 only has one ice cube relay for the fan and the clutch is handled by the Klima. So instead of jumping the relay like in the video I just used Klima pin 7 to activate the extra automotive relay.

Haven’t figured out a nice way to piggy back the connections yet. For the time being I jammed he wires in the holes like in your video.

Thanks Jarod. I love free (had a T and relay in the junk box) fixes. I’m going to drive out now and see how it works.

I guess if I need more cooling there’s the double condenser trick and isobutane refrigerants. Hopefully this will get me another few degrees.

If I could figure out what pins and sockets I could use, I'd 3d print a snap together adapter of some kind, or a whole harness that would just plug in and replace the "ice cube" relays with modern ones so it would all fit in the box nice and neat.

My cars AC has never been better, I've seen 36 degree vent temps when moving, it does seem to creep up when idling stopped, which could be because I've still got the old R12 style tube and fin condenser, or my R4 compressor is getting a bit tired, either way, I'll likely eventually do the parallel flow condenser mod and I've been thinking I want to pick up one of Rollguys sanden kits (I think its rollguy, someone on here makes them and they look beautiful and should be much more efficient than the old R4)

It works so good my wife has adjusted the temperature wheel up to around the 70f range rather than just leaving it on max cold.

I'm sure on some of the brutal humid and hot days it may still not be perfect, but little improvements along the way certainly make it a lot nicer to drive around.

I have heard of using air duster (R152A) as a replacement for R134a and performing much much better, I'm certain the EPA would have something to say about it, but the stuff literally gets blown into the air as part of its use, I've thought about trying that one day if anything happens to my 134a charge.

123boy · #20 07-26-2021, 01:03 PM

36 degree vent temps are WAAAAY TOO COLD!! Something is not right with your charge.
Always keep in mind that "vent temps" are about 20 degrees ABOVE the evaporator temperature. If your vent temps are indeed in the 30's that means your evaporator temperature is below 20 degrees (too cold). In an area with high humidity, the evap coil could freeze into a block of ice. This will then prevent air flow and the liquid refrigerant from flashing into a gaseous state (inside the evaporator to absorb heat/remove moisture from the air). That liquid will be sent back to the compressor (a liquid cannot be compressed) and then, blammo....there go your compressor valves. It sounds like your freon charge is low. What are the high and low side pressures on your gauges with the system operational? With the compressor engaged, the low side pressure should not be below freezing (pressure/temperature conversion chart)

Jarod · #21 07-26-2021, 02:03 PM

I haven't had any issues with evap icing as of yet, the ETR kicks the compressor off when the vent temps hit right about 36, and it kicks back on when the vents climb to 40.

There has never been excessive liquid coming from the condensate drain (it is connected, not just leaking into the carpet).

I'm measuring with a meat thermometer stuck in the center vents, so there is a good possibility it isn't super accurate, auto climate doing its magic as far as fan speed. I'm not sure if East TN qualifies as high humidity (77% @ 93F today) but it has been running just like this since last year when I made the evap cleaning video with no seeming issues, my wife has really enjoyed the cold air

I'm suspicious in your stating that 36 is too cold, as both of my diesel trucks (97 and 96/01 dodge) blow vent temps at or below that (same measurement with meat thermometer, so its at least consistent across vehicles), both of which are orifice tube style systems, much more basic than the TXV style system in our mercedes, and neither have ever issues with icing up.

I weighed in the charge into each vehicle myself, the w123 takes just a pinch over 2lbs of r134a if I did the calculation right, I don't recall high side pressure, but low side I feel like hovered around 50psi with the compressor running when I charged it, I have no clue what ambient temperature was then though, it has been a few years, maybe some has leaked off, but I would feel like cooling capacity would diminish if the charge was too low, the car has been frigid cold on every trip we've taken recently.

I'm certainly no expert on this stuff, I'm a marine mechanic by trade, you need info on your seadoo or boat, I can tell you whats what, I'd say I'm quite capable as a mechanic, engines and transmissions I can handle well, but A/C is relatively new to me, I got my section 609 certification a while back, but sitting in a room taking a test isn't my strong suit, I can answer the questions, but that doesn't mean I fully understood what I answered.
I don't absorb information well in a traditional classroom environment. I'll toss gauges back on the car for curiosity sake sometime soon, I'm in the middle of a brake system adventure right now

I would like to prevent my compressor failing if possible, at least long enough that when I decide to do the sanden conversion I don't have to think about the black death I dealt with on my grey w123

resago2000 · #22 07-26-2021, 02:24 PM

tell George we said hi

123boy · #23 07-26-2021, 03:03 PM

The fact you're not getting much condensate from the drain is a big indicator that something is amiss. There should always be a fair amount draining onto the ground (especially at 77% relative humidity). How does the amount draining out compare to your other vehicles? Naturally, if the humidity is low, there won't be as much. 77% is fairly high, though.
I realize it goes against natural instinct as far as "low charge, colder temps" is concerned, but, you can't always apply common sense/logic when dealing with ac. You have to apply/consider the golden rule of the "temperature/pressure relationship". In this case, pressure and temp are directly proportional. That is to say, as the pressure of the freon drops, it's temp drops. The lower the pressure (amount of charge in the system) the lower the temp of the gas.
You need to know the pressures (high and low) in the system at an increased engine speed (such as driving), not just idle. As compressor speed increases, the low side pressure drops, high side increases. I wouldn't be surprised if your low side pressure was dropping below freezing in this scenario. Your gauges should tell you freon temperature with corresponding pressure (psig).
If you don't have gauges with a 134a scale, just mark your pressure and find a conversion table online. I'm certainly no expert in this, as well. And not trying to be a "know it all". Just trying to shed a little light and share experience. Bottom line, this is all governed by the laws of physics. And, as everyone knows, you can't change the laws of physics. http://www.nethmalperera.ca/uploads/6/1/2/9/61293007/9075132.jpg?708
Also wanted to add: Vent temps being approx. 20 degrees above evaporator temp is not my opinion. This is fact. "Settled science" as they say....lol If nothing else, one would have to agree, vent discharge air in the mid 30's has to be above the evap core temp., right? So, regardless, that evap temp is getting awfully close to freezing. Again, laws of physics.

Jarod · #24 07-26-2021, 08:00 PM

Quote:

Originally Posted by resago2000

tell George we said hi

I would, but he's napping currently. Gotta get his beauty rest, lets face it, I'd just scare everyone off if I didn't have him to help out.

He's such a good little helper, always has some kind of input on whatever project I'm working on... Most of the time its "stop talking to that camera and pay attention to me".

I'll let him know how famous he is!

Jarod · #25 07-26-2021, 08:03 PM

Quote:

Originally Posted by 123boy

The fact you're not getting much condensate from the drain is a big indicator that something is amiss. There should always be a fair amount draining onto the ground (especially at 77% relative humidity). How does the amount draining out compare to your other vehicles? Naturally, if the humidity is low, there won't be as much. 77% is fairly high, though.
I realize it goes against natural instinct as far as "low charge, colder temps" is concerned, but, you can't always apply common sense/logic when dealing with ac. You have to apply/consider the golden rule of the "temperature/pressure relationship". In this case, pressure and temp are directly proportional. That is to say, as the pressure of the freon drops, it's temp drops. The lower the pressure (amount of charge in the system) the lower the temp of the gas.
You need to know the pressures (high and low) in the system at an increased engine speed (such as driving), not just idle. As compressor speed increases, the low side pressure drops, high side increases. I wouldn't be surprised if your low side pressure was dropping below freezing in this scenario. Your gauges should tell you freon temperature with corresponding pressure (psig).
If you don't have gauges with a 134a scale, just mark your pressure and find a conversion table online. I'm certainly no expert in this, as well. And not trying to be a "know it all". Just trying to shed a little light and share experience. Bottom line, this is all governed by the laws of physics. And, as everyone knows, you can't change the laws of physics. http://www.nethmalperera.ca/uploads/6/1/2/9/61293007/9075132.jpg?708
Also wanted to add: Vent temps being approx. 20 degrees above evaporator temp is not my opinion. This is fact. "Settled science" as they say....lol If nothing else, one would have to agree, vent discharge air in the mid 30's has to be above the evap core temp., right? So, regardless, that evap temp is getting awfully close to freezing. Again, laws of physics.

I really appreciate your input and suggestions, and you're right on all counts. I may well have an issue with my vent temps getting lower than expected, or perhaps it is the manner I've been testing them.

Either way, I'm convinced I need to reassess my pressures, and temperatures with the proper procedures, Perhaps I've got a teeny tiny leak somewhere and my charge has crept down.

I'll start poking and prodding once I get the brakes put back together (was changing pads and found a stuck piston and torn seal on a caliper, so that has turned into a whole braking system overhaul)

WDBCB20 · #26 07-28-2021, 11:10 AM

[QUOTE=gregp1962;4177347]

Quote:

Originally Posted by ykobayashi

I washed out my evaporator with a garden hose. I just went in from the blower side. I shot some photos inside before and after with a usb borescope. It had a lot of dust in the fins that washed out of the drains.

What is the best way to access the evaporator to clean it? Pics?

THe only way other than removing the entire dash and contents is to remove the blower. Attached is a pic of crud accumulated in a w126 evap.

WDBCB20 · #27 07-28-2021, 11:22 AM

Quote:

Originally Posted by ykobayashi

I guess if I need more cooling there’s the double condenser trick and isobutane refrigerants. Hopefully this will get me another few degrees.

The hydrocarbon (duracool, envirosafe) should get you 5 to 10 degrees colder. Also less wear on your compressor. Turning on the AC when I used to run R134 would really slug the compressor (reflected also in a sharp drop at the tachometer). Running it on hydrocarbon the impact was almost imperceptible.